Come on, you can be honest. Everybody has at least one discretionary spending indulgence that deserves a good belt tightening. Dining out? Clothing? Entertainment? Online shopping? Morning lattes?

It’s easy for those discretionary expenses to get lost in the noise of all your other transactions. By the time you tally everything up at the end of the month (assuming you’re doing that — wink, wink, nudge nudge!), even that seemingly innocuous habit can add up to a big number. The damage is done. As Ben Franklin wisely said: “Beware of little expenses; a small leak will sink a great ship.” So, you vow to reform next month, and the next month, and...

How do you break the cycle? Here’s a very simple recipe for isolating and trimming your fattest money habit.